Steam-turbine construction



May 28, 1929. FREY STEAM TURBINE CONSTRUCTION Filed Feb. 12, 1926 Patented May 28, 1929.

UNITED s:-TAT=E;s

PATENT oFrmE;

KARL FREY, F ENNETBADEN, SWITZERLAND, ASSIGNQB TO AKTIENGESELLSCHAFT {BROWN BOYERI & 0113., OF BADE'N, SWITZERLAND, A JOINT-STOCK COMPANY OF SWITZERLAND.

STEAM-TURBINE CONSTRUCTION.

Application filed February 12,1326, Serial No. 87,740, andin Germany February'M, 1925.

This invention relates to steam turbines and has as its general object the provision of a construction which contributes to facil- .ity and economy of manufacture andefii ciency of performance.

One of the specific objects is the provision of aconstructionrequiring blades ofonly one height throughout, on either the rotor or the cylinder or both, or throughout extensive groups of .stages. This simplifies and cheapens production, lessens the number ofblades which must be made for overage,-greatly decreases the number of unlike parts,jand from the standpoint ,of the user, is of great advantage in that it requires his keeping on handfor repair only one or two different types of blades.

Another object is the provision of a construction which gains these advantages with a rotor and .cylinder design which is simple and admits of economical manufacture and assembly with facility.

A further object is the provision of a construction in which the aforementioned advantages are secured without sacrifice of efficiency in operation.

Other and further objects and advantages will be pointed out hereinafter, indicated in the claims, or obvious to one skilled in the art upon an understanding of the present disclosures. V

In the accompanying drawing forming a part of this specification the nature of a construction embodying the invention is illust'rated diagrammatically, it being intended that the invention may take various struc'- ural forms, all within the scope of the ap-' pended claims.

In the drawing,

Fig. 1 is a graph illustrating in a general way the expansion of steam from stage to stage in a turbine,

Fig. 2 is a diagrammatic illustration in the nature of a part longitudinalsection through a part of the casing and rotor of an impulse turbine embodying the invention, and Fig. 3 is a diagrammatic illustration in the nature of a part longitudinal section through a portion ofa turbine of the reaction type in which the invention is embodied.

In turbine construction it is customary to increase the height of the blading from stage to stage or fromgone to another of groups of stages ofuniform diameter, for the purpose of accommodating the increasingfvolume of the expandingsteam. This necessarily involves the provision of blades of several heights,

requiring variety in the treatment of material from which they are cut and mul tlplication of handling operations, overage requirements, etc. My invention provides a construction wherein blades of uniform height may beused throughout, and high efliciency in operation attained. This ;I accomj lish by progressively increasing the blading diameter in successive stages by suchjincre- .ments as will give the requisiteadmission inder is, of course, determined for the most part by the bladingdiam'eters.

In Fig. 2 is shown diagrammatically an illustrative structure in which the numeral 10 designates a portion of the rotor shaft. and 11 i a section of the cylinder or casing. On the rotor discs 12 are carried the rotor blades (Z (Z 0Z (Z and on the stator discs or diaphragms 14 the guide blades 0 c 0 o The blades on the several discs 12 are of uniform height and form, as are also those on the several guide discs 14. The jblading diameter of the several stages is determined in substantial accordance with the'steam volume curve I along the blading, shown in Fig. 1. On the,

graph the volume at the outlets from the blading of the respective guide and rotor stages i is indicated by the points a 6 a 6 etc. The several diameters are so establishedas to peripheral velocity m h who '5 i steam velocity substantially uniform for all, stages, the ad mission area in each instance having the same derived from the increased diameter of the blading and the consequent increase of-cross 'radiae extent, the necessary increase being I eter. -Knowing the volume,'thediameters qS of the guide and rotorblading ma be calculatedfrom the formula G-o= f-o, w erein G is f is annular admission area and 0 is steam veloclty so, f=h-4 -1r and Ge h'dwr''. Accordis a constant). In disc turbines the construction may follow the. diameterdeterminations quite closely, and in reaction turbines of the drum construction the determinations may be followed, not With mathematical exactness, but ,vvithout's'erious or substantial variation l v I it I u l from, a unlform ratio of Z by a structureln which the rotor drum is formed with a conical peripheral surface.- Such a construction is illustrated in' a general Way in Fig. 3, the numeral 12 designating the conical drum, the characters 0 0- 0 stator blades, d d d rotor blades, and 11 the casing. The blading, on stator and rotor, is of uniform height, and the surfaces of the drum and easing bore are parallel. It will be seen that, in such constructions particularly, the invention con tributes greatly to simplification of manufacture and assembly.

WVhatIc'laim is: i 1

1. A multi-stage steam turbine having r0- tor blades of uniform height and the blading diameter and admission area increasing from stage to stage by amounts maintaining the ratio of peripheral velocity to steam velocity substantially uniform.

2. A multi-stage steam turbine having full admission and the blades of uniform height throughouhthe blading diameter increasing from stageto stage by amounts such as to maintain the ratio of peripheral velocity to steam velocity substantially uniform.

In a multi-stage steam turbine, a casing having a conical bore surface, a rotor drum having .a conical peripheral surface, blades being on said casing and drum of imiform height throughout, and blading diameter increasing from stage to stage in uniform ratio such as to maintain the ratio of peripheral velocity to form; 7

4. A turbine construction as specified in claim 3, having the rotor and casing bore surfaces parallel.

5. A multi-stage steam turbine having blades of uniform height in different stages, the blading diameter of the respective stages being such as to maintain theratio of peripheral velocity to steam velocity substantially uniform'for all stages.

In testimony whereof I have hereunto subscribed my name at Zurich, Switzerland on the 20th day of January, A. D. 1926.

KARL FREY.

steam velocity substantially uni- 

